docs: def from_interval_shorthand(self, startnote, shorthand, up=True):
          """Empty the container and add the note described in the startnote and
          shorthand.
  
          See core.intervals for the recognized format.
  
          Examples:
          >>> nc = NoteContainer()
          >>> nc.from_interval_shorthand('C', '5')
          ['C-4', 'G-4']
          >>> nc.from_interval_shorthand('C', '5', False)
          ['F-3', 'C-4']
          """
          self.empty()
          if type(startnote) == str:
              startnote = Note(startnote)
          n = Note(startnote.name, startnote.octave, startnote.dynamics)
          n.transpose(shorthand, up)
          self.add_notes([startnote, n])
          return self